The present invention relates to a yarn winding method, and the resulting package, and which is particularly adapted for use in winding freshly spun and/or drawn synthetic filament yarns to form cylindrical cross-wound packages having flat end faces.
Cross-wound packages of synthetic filament yarn, and which are produced at a constant traversing speed, or at least within predetermined limits of a constant traversing speed, often have bulges and beads both on their circumferential surface and their end faces. The bulges on the end faces, which are generally of arcuate configuration in cross section, not only adversely affect the appearance of the package, but they also affect its quality in that so-called castoffs or sloughs develop in the areas of the bulges. These castoffs are formed by yarn lengths which slip out of the body of the package and onto the end face and span the end face in the manner of a secant over one or several yarn layers. Such castoffs cause difficulty in unwinding the yarn, particularly where the yarn is intended to be withdrawn at high speeds from the package.
It is accordingly an object of the present invention to produce a yarn package with good unwinding properties, and which is free of castoffs.
It is also an object of the present invention to provide a yarn winding method which produces a stable package, and which has an essentially cylindrical shape and does not exhibit either contractions or bulges on its end faces.
It is a further object of the present invention to provide a yarn package wherein the yarn layers of the package are stable, in that the yarn lengths deposited in the reversal areas of the package do not tend to slip toward the center of the package during unwinding. Such slippage can result in the slipped yarns overlying the yarn windings located further outwardly, so as to clamp these outwardly lying yarns during the unwinding.
It is also an object of the present invention to provide a yarn winding method of the described type and wherein the tension forces which are operative on the yarn being wound, are not subjected to significant fluctuations.